Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS5301672 A
Publication typeGrant
Application numberUS 07/977,053
Publication dateApr 12, 1994
Filing dateNov 16, 1992
Priority dateDec 9, 1991
Fee statusLapsed
Also published asDE4218321A1
Publication number07977053, 977053, US 5301672 A, US 5301672A, US-A-5301672, US5301672 A, US5301672A
InventorsWilli Kalender
Original AssigneeSiemens Aktiengesellschaft
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Radiological diagnostics system employing a contrast agent
US 5301672 A
Abstract
In a diagnostics system wherein a radiological image is generated of a patient who has been injected with a contrast agent, the arrival of the contrast agent bolus at the imaging site is identified either directly by detecting the contrast agent, or indirectly by detecting a dye injected with the contrast agent, so that a synchronization of the imaging exposures with the arrival of the contrast agent can be assured. If a dye is used, the dye can be an optically detectable dye which is injected via the contrast agent syringe in addition to the contrast agent. A densitometer identifies the arrival of the contrast agent or of the dye at a predetermined location of the patient, and controls triggering of the exposures.
Images(1)
Previous page
Next page
Claims(3)
I claim as my invention:
1. A diagnostics system comprising:
means for generating a radiological image of a patient;
means for introducing a contrast agent and a contrast agent indicator into said patient;
means for identifying the in vivo concentration of said contrast agent in said patient at a predetermined location in the body of said patient by monitoring the presence of at least one of said contrast agent or said contrast agent indicator at said location, and for generating an electrical signal corresponding to said concentration; and
means for triggering generation of said radiological image when said signal reaches a predetermined level.
2. A diagnostics system as claimed in claim 1 wherein said means for introducing a contrast agent and a contrast agent indicator is a syringe system.
3. A diagnostics system as claimed in claim 1 wherein said contrast agent indicator is an optically detectable dye, and wherein said means for identifying the in vivo concentration of said contrast agent is a means for optically monitoring the presence of said optically detectable dye at said location on the body of said patient.
Description
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to a radiological diagnostics system of the type wherein a radiological image of an examination subject, who has been injected with a contrast agent, is generated.

2. Description of the Prior Art

For many radiological investigations, it is desirable to trigger the imaging exposure, after the injection of a bolus of contrast agent, at exactly the time of arrival of the bolus of contrast agent in the organ or body region of interest, in order to achieve optimum contrast and/or to completely image the bolus if the examination is a dynamic examination. A problem in obtaining such exact triggering is that the passage time of the intravenously injected bolus (usually injected into the vein of an arm) through the right atrium, right ventricle, circulation through the lungs, the left atrium and left ventricle and to the organ of interest varies greatly from patient to patient. In addition to being dependent on parameters such as the heart rate, which can be relatively easily acquired, this passage time is dependent on other parameters which cannot be reliably monitored. A current problem is to obtain such synchronization in the context of spiral computer tomography, wherein complete organs or body sections are to be examined in the shortest possible time, and thus exact synchronization of the imaging with arrival of the contrast agent bolus is necessary. Frequently, a portrayal of blood vessels (CT angiography) is also desired. The triggering problem, however, is present in all examinations which require an injection of a contrast agent.

The above problem has not been exactly resolved, but has heretofore been approximately resolved by relying on the experience of the physician or radiologist. The examining person acquires the appropriate experience through examination employing transillumination monitoring, for example in digital subtraction angiography. Recommendations for estimating the passage time after injection of the contrast agent bolus, primarily dependent on the pulse rate, have been developed on the basis of such examinations and other fundamental studies. Such procedural rules, however, provide only approximate suggestions, resulting in the imaging exposure being triggered too early or too late in many instances, particularly in the case of examining personnel with less experience. If the x-ray imaging is triggered prematurely, this results in an unnecessary increase in the radiation dose to the patient. If the x-ray imaging is triggered too late, the image of the bolus is not completely acquired, which can mean that the results of the examination are not useable, and the entire examination must be repeated. The problem does not lend itself to a procedural protocol which is applicable in all examinations since, for example, the circulation parameters of a patient can change very rapidly.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a radiological diagnostics system of the type wherein the patient is injected with a contrast agent, wherein an exact synchronization of the imaging exposures with the course of the contrast agent is achieved, so that the exposures are made at a time when the contrast agent optimally fills the body region under examination.

The above object is achieved in accordance with the principles of the present invention in a diagnostics system wherein the circulation or diffusion of the contrast agent in the arterial system is monitored by a densitometer at a predetermined location of the patient, with the triggering of the exposures being controlled by the densitometer output. The contrast agent detection can ensue directly by measuring concentration of the contrast agent itself, for example on the basis of a low-energy and low-intensity radioisotope source. Alternatively, the contrast agent detection can be made indirectly by injecting an optically detectable dye as a contrast agent indicator into the patient through the contrast agent syringe in addition to the contrast agent. The course of the contrast agent can then be acquired by an optical densitometer. As used herein generically, however, the term "densitometer" means any type of instrument for identifying the in vivo concentration (density) of the contrast agent at a given location in the body.

The imaging exposures are then triggered at a time when the proper contrast agent occupation of the region under examination is present, by synchronizing the triggering of the exposures with the output signals of the densitometer. If necessary, a predetermined delay can be incorporated between the time at which the contrast agent concentration is measured at the selected body location and the actual triggering.

DESCRIPTION OF THE DRAWINGS

The single FIGURE is a schematic block diagram of a diagnostics system constructed in accordance with the principles of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in the drawing, a diagnostics installation constructed in accordance with the principles of the present invention includes an x-ray tube 1 which is operated by a high-voltage generator 10 so as to generate an x-ray beam 2 which transilluminates a patient 3. The radiation attenuated by the patient 3 is incident on the input screen of an x-ray image intensifier 4, having a video camera 5 which generates video signals corresponding to the x-ray (radiological) image for processing by video electronics 6. The video electronics 6 includes a television monitor (not separately shown) on which the image is visually displayed. The preparation of the x-ray exposures is controlled and synchronized by a control unit 7, connected both to the high-voltage generator 10 and to the video processing electronics 6. A syringe system 8 is provided for injecting a contrast agent into the patient 3. The contrast agent may be injected through the syringe system 8 in combination with a contrast agent indicator, such as an optically detectable dye. If a dye is used in combination with the contrast agent, this can be mixed with the contrast agent in a single drip bottle or drip packet, or separate drip bottles or packets can be used for the contrast agent and for the dye, combined by means of a Y-coupling in the syringe system 8, or by other suitable means.

the concentration of the contrast agent or the added dye (indicator) is acquired by a densitometer 9, which in the exemplary embodiment of FIG. 1 is shown arranged at a finger of the patient 3. It will be understood that the concentration of the contrast agent or dye can also be monitored at some other body location, for example, at an earlobe. The densitometer 9 supplies electrical output signals to the control unit 7, which function as trigger signals for the imaging. Imaging is triggered when the output signal from the densitometer 9 indicates a suitable occupation of the contrast agent 9 in the arterial system which indicates a simultaneous optimum occupation in the imaging region, or which indicates that an optimum presence of the contrast agent in the imaging region will occur following a predetermined delay.

An example of indirect detection employing the system shown in the drawing is as follows. Shortly before, or simultaneously with, the injection of the contrast agent bolus, an optically detectable dye is injected into the patient 3 through the syringe system 8. The arrival of this dye in the arterial system is detected by a change in the light transmission in a peripheral body part, such as the finger of the patient 3. The densitometer 9 continuously transmits output signals to the control unit 7. The control unit 7 forwards a trigger signal to the high-voltage generator 10 and to the video processing electronics 6 for triggering generation of an exposure when the dye is detected in a specified concentration and when the signal reaches a predetermined level. The video processing electronics 6 or the video camera 5 can have a delay incorporated therein, dependent on whether the dye was injected shortly before the contrast agent bolus or simultaneously therewith.

Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventor to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of his contribution to the art.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US4459990 *Jan 26, 1982Jul 17, 1984Elscint, IncorporatedRadiographic method and apparatus for the visualization of the interior of a body particularly useful for the visualization of a subject's circulatory system
US4528178 *May 12, 1982Jul 9, 1985Biomedics, Inc.Chemotherapeutic agent and tracer composition and use thereof
US5005576 *Mar 30, 1989Apr 9, 1991Hewlett-Packard CompanySilicon glue which allows diffusion of gases
US5040538 *Sep 5, 1989Aug 20, 1991Siemens-Pacesetter, Inc.Pulsed light blood oxygen content sensor system and method of using same
US5057695 *Dec 15, 1989Oct 15, 1991Otsuka Electronics Co., Ltd.Method of and apparatus for measuring the inside information of substance with the use of light scattering
US5067494 *Dec 4, 1989Nov 26, 1991Siemens AktiengesellschaftDevice for generating trigger signals for a medical apparatus dependent on the respiratory activity of a patient
US5074309 *Dec 4, 1989Dec 24, 1991Sperry Marine Inc.Device for monitoring cardiovascular signals and fiber optic coupler phonocardio sensor therefor
US5128121 *Apr 6, 1989Jul 7, 1992Nycomed AsMixture of a positive and negative contrast agent for magnetic resonance imaging
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5383456 *Mar 17, 1994Jan 24, 1995The Ohio State University Research FoundationRadiation-based laparoscopic method for determining treatment modality
US5687208 *May 15, 1996Nov 11, 1997Bhb General PartnershipFor scanning a tissue in a patient
US5694935 *Nov 12, 1996Dec 9, 1997Fonar CorporationGastrointestinal magnetic resonance imaging
US5924987 *Oct 6, 1997Jul 20, 1999Meaney; James F. M.Method and apparatus for magnetic resonance arteriography using contrast agents
US6167293 *Apr 19, 1996Dec 26, 2000General Electric CompanyMethod for performing magnetic resonance angiography using a contrast agent
US6240311Jul 29, 1998May 29, 2001Martin R. PrinceMethod and apparatus for magnetic resonance imaging of arteries using a magnetic resonance contrast agent
US6337992 *Jan 29, 1997Jan 8, 2002Philips Medical Systems Technologies Ltd.Predictive bolus tracking
US6397098 *Apr 27, 1999May 28, 2002Medrad, Inc.Data communication and control for medical imaging systems
US6463318Apr 7, 2001Oct 8, 2002Martin R. PrinceMethod and apparatus for magnetic resonance imaging of arteries using a magnetic resonance contrast agent
US6564085Oct 23, 2001May 13, 2003James F.M. MeaneyMethod and apparatus for magnetic resonance arteriography using contrast agents
US6741881Aug 5, 2002May 25, 2004Martin R. PrinceMethod and apparatus for magnetic resonance imaging of arteries using a magnetic resonance contrast agent
US6754521Feb 27, 2003Jun 22, 2004Martin R. PrinceMethod and apparatus for magnetic resonance imaging of arteries using a magnetic resonance contrast agent
US6879853Jan 24, 2003Apr 12, 2005James F. M. MeaneyMethod and apparatus for magnetic resonance arteriography using contrast agents
US6889072Jul 5, 2001May 3, 2005Martin R. PrinceMethod and apparatus for administration of contrast agents for use in magnetic resonance arteriography
US6970735 *Apr 29, 2002Nov 29, 2005Medrad, Inc.Data communication and control for medical imaging systems
US7221729 *Apr 12, 2006May 22, 2007Kabushiki Kaisha ToshibaX-ray computer tomography apparatus
US7313216 *Aug 8, 2005Dec 25, 2007Ge Medical Systems Global Technology Company, LlcScan control method and X-ray CT apparatus
US7313428Dec 3, 2004Dec 25, 2007Meaney James F MMethod and apparatus for magnetic resonance arteriography using contrast agents
US7380985Apr 18, 2007Jun 3, 2008Ge Medical Systems Global Technology Company, LlcX-ray detecting apparatus and x-ray imaging apparatus
US7606614 *Aug 30, 2006Oct 20, 2009General Electric CompanyPrediction methods and apparatus
US7672710 *Aug 2, 2005Mar 2, 2010Medrad, Inc.Data communication and control for medical imaging systems
US7680527Jul 26, 2006Mar 16, 2010Prince Martin RMethod and apparatus for imaging abdominal aorta and aortic aneurysms
US7689267Mar 25, 2004Mar 30, 2010Prince Martin RMethod and apparatus for magnetic resonance imaging of arteries using a magnetic resonance contrast agent
US7747309Mar 25, 2004Jun 29, 2010Prince Martin RMethod and apparatus for administration of contrast agents for use in magnetic resonance arteriography
US7937134May 23, 2007May 3, 2011Medrad, Inc.Systems for controlling injection and/or imaging procedures
US8055328Aug 4, 2009Nov 8, 2011Medrad, Inc.Interface unit for use with injectors and imaging systems and related devices
US8160679Jun 3, 2009Apr 17, 2012Medrad, Inc.Methods of coordinating an imaging procedure and an injection procedure
US8197437Mar 27, 2007Jun 12, 2012Medrad, Inc.Systems and methods of modeling pharmaceutical propagation in a patient
US8295914Nov 16, 2005Oct 23, 2012Medrad, Inc.Systems and methods of determining patient transfer functions and modeling patient response to a pharmaceutical injection
US8315449Jun 24, 2008Nov 20, 2012Medrad, Inc.Identification of regions of interest and extraction of time value curves in imaging procedures
US8346342Jul 7, 2011Jan 1, 2013Medrad, Inc.Systems and methods of determining patient physiological parameters from an imaging procedure
US8428694Jun 24, 2008Apr 23, 2013Medrad, Inc.Methods for determination of parameters for a procedure, for estimation of cardiopulmonary function and for fluid delivery
US8452380Apr 21, 2005May 28, 2013Acist Medical Systems, Inc.Interface device and protocol
US8608484Mar 4, 2009Dec 17, 2013Medrad, Inc.Dynamic anthropomorphic cardiovascular phantom
US8699770Oct 19, 2012Apr 15, 2014Bayer Medical Care Inc.Identification of regions of interest and extraction of time value curves in imaging procedures
CN1732851BAug 12, 2005Aug 17, 2011Ge医疗系统环球技术有限公司Scan control method and x-ray CT apparatus
EP1765173A2 *Apr 21, 2005Mar 28, 2007E-Z-EM, Inc.Interface device and protocol
WO1997012550A1 *Sep 30, 1996Apr 10, 1997Bhb L CPredicting ct contrast enhancement with feedback
Classifications
U.S. Classification600/428, 378/97, 600/431, 600/500
International ClassificationA61B6/00
Cooperative ClassificationA61B6/481, A61B6/504
European ClassificationA61B6/48B, A61B6/50H
Legal Events
DateCodeEventDescription
Jun 11, 2002FPExpired due to failure to pay maintenance fee
Effective date: 20020412
Apr 12, 2002LAPSLapse for failure to pay maintenance fees
Nov 6, 2001REMIMaintenance fee reminder mailed
Sep 12, 1997FPAYFee payment
Year of fee payment: 4
Nov 16, 1992ASAssignment
Owner name: SIEMENS AKTIENGESELLSCHAFT, GERMANY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:KALENDER, WILLI;REEL/FRAME:006342/0276
Effective date: 19921111